How to quickly convert videos from Instagram or Vine to GIF or MP4 without losing quality?

Hello, community! I often work with short videos from Instagram, Vine or Twitter and want to quickly convert them to GIF, WebM or MP4 for the website. I need a simple API that accepts any links (Giphy, Imgur, etc.), transcodes them instantly, and outputs an optimised player. Can anyone recommend a reliable service? Thank you!